I've got a few favorites that I read over and over ad nauseum, they are old friends that when you start reading them, it's like you are sitting on the 50 yard line just watching the story unfold. Well, anyway here goes nothing:
Anne McCaffrey:
Her DragonRiders of Pern
The Rowan Series
The Freedom Series
Acorna
Ship/Brawn Series
and a few stand alones: Nimisha's Ship, and Restoree
Mercedes Lackey:
Anything about her world of Valdemar
Mercedes Lackey/James Mallory team up:
The Obsidian Trilogy
The Enduring Flame Trilogy
Jack McDevitt: Anything he's got out. It's on the same genre as Arthur C. Clarke, but he makes you think more. I think he puts more mystery into things. He's dang good!
And Last but not Least:
David and Leigh Eddings:
The Belgariad Series
The Mallorian Series
Belgarath
Polgara
The Elenium Series
The Tamuli Series
The Redemption of Althalus
Those are my main ones I read, even though I do diverge off and read a time-travel romance or two or three as the whim takes me. And if I truly want to read some light stuff I've got all the books to Calvin & Hobbes, Opus, Fox Trot, For Better or For Worse, Baby Blues, Zits, Stone Soup, and Peanuts to read. As well as some graphic novels (all consisting of ElfQuest).